Meltblown nonwoven fibrous webs are used for a variety of purposes including filtration (e.g., flat web and pleated filters), insulation, padding and textile substitutes. Patents or patent applications relating to meltblown nonwoven fibrous webs include U.S. Pat. Nos. 3,959,421 (Weber et al.), 4,622,259 (McAmish et al.), 5,075,068 (Milligan et al.), 5,141,699 (Meyer et al.), 5,273,565 (Milligan), 5,405,559 (Shambaugh), 5,523,033 (Shambaugh et al.), 5,652,048 (Haynes et al.), 5,665,278 (Allen et al.), 5,667,749 (Lau et al.), 5,695,487 (Cohen et al.), 5,772,948 (Chenoweth) and 5,811,178 (Adam et al.), and Published PCT Application No. WO 95/03114 (University of Tennessee Research Corporation). Patents or patent applications relating to filters include U.S. Pat. Nos. 3,780,872 (Pall), 4,547,950 (Thompson), 5,240,479 (Bachinski), 5,709,735 (Midkiff et al.), 5,820,645 (Murphy, Jr.), 6,165,244 (Choi), 6,521,011 B1 (Sundet et al. '011) and D449,100 S (Sundet et al. 100), U.S. Patent Application Publication Nos. US 2003/0089090 A1 (Sundet et al. '090) and US 2003/0089091 A1 (Sundet et al. '091), and European Published Application No. 1 437 167 A1 (Morimura KKK).